Data processing systems are widely used to control industrial processes which move through a series of industrial process steps. An example of an industrial process which is controlled by a data processing system is a computer controlled design and manufacturing system. In a computer controlled design and manufacturing system, often referred to as a computer automated design/computer aided manufacturing (CAD/CAM) system, items are designed on a computer, and the system for manufacturing the designed item is controlled by computers.
In a CAD/CAM system the design of an item progresses through a series of steps, with the design of the item being represented on a computer database during all steps. Thus, for example, the design progresses from a development phase, to a pre-release phase, a release phase, and an accept phase. During the development phase, the design is typically developed and tested for implementation worthiness by test and development engineers. During the pre-release phase, the developed design is approved by various organizations until authority has been given to finalize the design. During the release phase, the design has been reviewed by appropriate authorities and is released for manufacturing.
An item is typically designed at one development location and is manufactured at multiple locations. Accordingly, during the accept phase, the design is accepted into a manufacturing location and manufacturing planners and engineers prepare the design so that it can be implemented in the shop floor at that location. The design then moves to an effective phase where the design has been approved by the manufacturing engineers and is ready to be implemented in the shop floor at a prescribed implementation date. Finally, the design is eventually phased out by placing it in a closed status. In a CAD/CAM system, the design of the item is developed, modified and then implemented for manufacturing on a computer platform rather than using traditional printed engineering blueprints and printed specifications.
After an item is designed and manufactured, an engineering change control process is also typically controlled by a data processing system. As is well known to those having skill in the art, an engineering change represents a change to the design of an item in a manufacturing environment. Similar to the design and manufacturing process for the item itself, an engineering change typically progresses through a series of industrial process steps including development, pre-release, release, accept, effective and closed. CAD/CAM systems typically represent engineering change control data and are used to control the engineering change control process. See for example U.S. Pat. No. 5,191,534 to Orr et al. entitled Engineering and Manufacturing Change Control Mechanism, which is assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference.
Industrial processes which are controlled by data processing systems are not limited to manufacturing processes. For example, in preparing a document for publication, the document itself typically undergoes phases of development, pre-release, release, accept, effective and closed along the lines described above. Similar steps are also involved in most business processes such as a business proposal or bid process or a budgeting process.
When using a data processing system to control industrial processes of the types described above, it is particularly important to protect the data security of the data processing system. The industrial process is typically represented by a large number of data elements in a database on the data processing system, and multiple users from multiple groups have access to the data. Since the data is ultimately used to design an item, such as a product, a document, or a budget, it is important that the data is not corrupted by the large numbers of people who have access to the data.
Many security control systems for data processing systems which share data have been proposed. See, for example, U.S. Pat. No. 4,525,780 to Bratt et al. entitled Data Processing Systems Having a Memory Using Object-Based Information and a Protection Scheme for Determining Access Rights to Such Information; U.S. Pat. No. 4,698,752 to Goldstein et al. entitled Data Base Locking; U.S. Pat. No. 4,713,753 to Boebert et al. entitled Secure Data Processing System Architecture with Format Control; U.S. Pat. No. 5,008,853 to Bly et al. entitled Representation of Collaborative Multi-User Activities Relative to Shared Structure Data Objects in a Networked Workstate Environment; and U.S. Pat. No. 5,133,075 to Risch entitled Method of Monitoring Changes in Attribute Values of Object in an Object-Oriented Database.
Notwithstanding this intense focus, there is a continuing need for a method and system for controlling security of data elements which represent an industrial process and which are manipulated by a plurality of users on a data processing system. There is a particular need for controlling security when the industrial process includes many industrial process steps which are practiced over an extended time period.